On August 20, 1897, Anopheles mosquitoes were shown, by British doctor Sir Ronald Ross, to be responsible for the transmission of the malaria parasite – a breakthrough in vector-borne diseases. Three centuries earlier the word “mosquito” entered the English language – now referring to any of the slender long-legged dipteran (two-winged) flies with aquatic larvae, of the Culicidae family, especially the genera Culex, Anopheles and Aedes, whose females’ long proboscis is used to puncture animals’ skins to suck their blood. This was a post-Columbian borrowing from the Spanish mosquito , composed of mosca , from the Latin musca “fly”, plus - ito , the Spanish diminutive suffix. Previously, English had used “gnat” for such insects. It was only in England’s 16th century global explorations, when varieties “exceedingly troublesome in some parts of the West Indies and America” were encountered, that a new word become warranted, and adopted. It is first documented in several English travel accounts, in particular those of Richard Hakluyt – whose works are widely acknowledged as having promoted English colonisation of North America – as “A certeine gnat or flie which they call a Muskito, which biteth both men and women in their sleepe” (1572) – “the Spanyards called them Musketas” (1589). Much variation in the word’s spelling is observed over the centuries. Early dictionaries such as The New World of English Words (1658) and An English Dictionary (1692) give “muscheto”, the latter mentioning the Italian moschetta as its source, which explains their -ch- choice of spelling. Muscheto / moschetto variants dominate through the 18th century. (Curiously, English writer Samuel Johnson’s 1756 pre-eminent dictionary has no such entry, sticking with “gnat”.) The -k- spelling recurs when American lexicographer Noah Webster, as part of his simplified spelling scheme, introduces “musketoe” in his 1806 and 1828 dictionaries, but this did not take. Webster’s 1847 edition introduces an entry for “mosquito”, redirecting to musquito, listed alongside musketo (where a note insists that the latter “anglicised form would be preferable”). This -q- spelling may well have been due to the knowledge of Romance language rules that when a suffix beginning with “i” is added to a word ending in “c” in Spanish, “c” becomes “q”. By the 1860s, this had become established in major dictionaries.